In the chemical, pharmaceutical and basic industry, pulverulent solids such as powder, grain or mixtures thereof are as raw materials further processed into smaller units, e.g. pellets (pills, tablets). Problems during said further processing may be caused in particular by the high air content or a lack of pourability. Therefore, the pulverulent raw material is commonly at first compacted and granulated prior to a further processing. For that purpose, the raw material is usually by means of an auger feed precisely dosed and steadily fed to the press rolls of a roller press. Though the pressing of the pulverulent raw material between two press rollers, a homogenous, rigid, high dense and usually strip shaped coarse material, also called “flakes” (German “Schülpe”), is obtained as intermediate product. The flakes, produced by the compacting, are granulated to the desired spectrum of grains by means of a single or multiple stage granulator, which presses the flakes though a screen by a rotor. A well pourable granulate can thus be obtained with very low air content and predefined grain size, which can usually be further processed or pressed, respectively into smaller units, like pellets, also without the use of chemical additives such as binder. Such a granulator can be provided as a separate machine or be combined together with a compacting apparatus in a single machine.
Adjusting a distance between rotor and screen commonly occurs manually. Therefore, the production effectiveness and granulate quality usually underlie fluctuations.